Computer aided design and drafting (CADD) was used to plan safety improvements for the Dan Ryan Viaduct, a two mile expressway in Chicago. Some 17 accidents per day took place along the viaduct before design was initiated. Construction of the improvements, which include widening and reshaping of exit/entrance ramps, is underway. CADD was performed on microcomputers using standard CADD programs enhanced by additional programming. The article not only describes this specific CADD project, it also discusses the current state of CADD.